SECRET AGENT

Internet users typically reveal their IP addresses, and this lets companies compile a profile of your Internet activities. Tor and Privoxy can help protect your privacy.

The epidemic of Internet-based market research continues: many companies routinely investigate their customers’ Internet surfing habits – a cheap and transparent form of spying. And in some repressive countries, the government may even be watching where you surf. Privoxy [1] and Tor [2] puts the spies off your trail. A browser typically talks directly to a remote target, most commonly a website, and the web server that hosts the site logs the corresponding access data. The Tor client prevents your requests from going directly to the target; instead the requests are forwarded via a proxy running on your home machine through a number of nodes to a so-called exit node, which then talks to the target machine (Figure 1). The server version of Tor acts as one of the intermediate nodes in the chain. The name “Tor” is an acronym for The Onion Router. Private users will more typically run Tor as a client, commonly known as an the Onion Proxy.